The present invention relates to a lead for use with an implantable medical device. More particularly, the invention relates to a multiple lumen, multiple conductor, pacemaker lead.
Permanently implantable electrical lead systems are used in conjunction with implantable medical devices, such as pacemakers, nerve and muscle stimulators and anti-tachycardia devices. In these applications the lead is used to transmit electrical signals to and/or from the medical device. Leads of this type may be chronically implanted and are expected to exhibit a long service life in a hostile environment of the human body.
The traditional lead includes a lead body having a generally circular exterior cross-section and one or more circular lumens, which may be arranged coaxially or parallel to one another. Typically, spiral wound metallic conductors are positioned within one or more lumens of the lead body. The spiral wound conductor also forms a lumen which can receive a stylet to help stiffening the lead as an aid to lead placement during lead implantation.
Alternative conductor designs have been proposed in the context of implantable multiple lumen multiple conductor leads. U.S. Pat. No. 4,608,986 issued to Beranek discloses a round lead having an array of round lumens. This lead places a single "straight" strand of metallic conductor loosely into each lumen. An exotic metal formulation is stated to avoid the problems of breakage due to flexing normally associated with straight conductors. An additional alternative conductor for use in implantable leads is bundled, stranded wire, as disclosed in U.S. Pat. No. 4,964,414, issued to Handa et al.